I certainly don't think there were any Dragons left. Minor Wyrms maybe. Probably some orcs left hiding in the mountains etc..

The Balrog has possibilities to.

TreeBeard......

: There may have been another Balrog unaccounted for that arose from the ruin of Sauron's reign. The Silmarillion certainly suggests more than one got away to bury themselves under the earth. Not all of Sauron's servants were killed - possibly one of his more adept students that although never mentioned before, may have existed. Or a student of The Mouth. The fact that The Mouth was one of Sauron's lacky's certainly suggests that there MAY have been others. And if such a minion had any sorcerous powers at all, who was left in Middle Earth to combat him/her?

: There may have even been some dragons left in The Grey Mountains and the Withered Heath!

: Who knows but the potential for more evil minions of Morgoth to raise their ugly heads is certainly there.

: Padster

: : Plus, you have to refer to the second prophecy of Mandos. Mandos fortells the return of Morgoth.

: Yeh! But that all happened over in Valinor and doesn't really effect Middle Earth.